M701F联合循环机组余热锅炉启动过程优化研究

针对三菱M701F级燃气-蒸汽联合循环机组经常参与调峰而涉及到频繁启停,且余热锅炉因惯性大而启动慢的特点,结合余热锅炉的工作原理及相关特性 ,为了缩短余热锅炉启动时间,提出了一种启动优化模型。该方法以APROS(Advanced Process Simulation Software)模型为基础,综合理论分析和经验归纳,对余热锅炉内部各模块进行了详细的仿真研究。仿真结果表明,以APROS为基础的优化模型能够在准确模拟余热锅炉稳态运行工况的同时缩短至少20%的启动时间,对联合循环机组整体的运行优化有很大的帮助。     

余热锅炉仿真建模方法的探讨

作为燃气蒸汽联合循环系统中的重要设备，余热锅炉对整个系统的性能起到决定性作用。应用仿真技术进行余热锅炉系统性能研究是一项切实可行的方法，也是进行余热锅炉设计的重要辅助手段。列举了余热锅炉结构及热力特性，系统划分、建模方法、参数选取、二次建模等，并对建模及计算方面要注意的问题进行了详细的阐述。     

余热锅炉快速启动的影响因素及实现措施分析

根据余热锅炉的运行及研究现状,阐述余热锅炉快速启动的意义及余热锅炉的启动方式,分析余热锅炉快速启动的影响因素,对实现余热锅炉安全、快速启动的措施进行了论述。     

A performance analysis of integrated solid oxide fuel cell and heat recovery steam generator for IGFC system

Solid oxide fuel cell (SOFC) is a promising technology for electricity generation. Sulfur-free syngas from a gas-cleaning unit serves as fuel for SOFC in integrated gasification fuel cell (IGFC) power plants. It converts the chemical energy of fuel gas directly into electric energy, thus high efficiencies can be achieved. The outputs from SOFC can be utilized by heat recovery steam generator (HRSG), which drives the steam turbine for electricity production. The SOFC stack model was developed using the process flow sheet simulator Aspen Plus, which is of the equilibrium type. Various ranges of syngas properties gathered from different literature were used for the simulation. The results indicate a trade-off efficiency and power with respect to a variety of SOFC inputs. The HRSG located after SOFC was included in the current simulation study with various operating parameters. This paper describes IGFC power plants, particularly the optimization of HRSG to improve the efficiency of the heat recovery from the SOFC exhaust gas and to maximize the power production in the steam cycle in the IGFC system. HRSG output from different pressure levels varies depending on the SOFC output. The steam turbine efficiency was calculated for measuring the total power plant output. The aim of this paper is to provide a simulation model for the optimal selection of the operative parameters of HRSG and SOFC for the IGFC system by comparing it with other models. The simulation model should be flexible enough for use in future development and capable of predicting system performance under various operating conditions.     

A performance analysis of integrated solid oxide fuel cell and heat recovery steam generator for IGFC system

Solid oxide fuel cell (SOFC) is a promising technology for electricity generation. Sulfur-free syngas from a gas-cleaning unit serves as fuel for SOFC in integrated gasification fuel cell (IGFC) power plants. It converts the chemical energy of fuel gas directly into electric energy, thus high efficiencies can be achieved. The outputs from SOFC can be utilized by heat recovery steam generator (HRSG), which drives the steam turbine for electricity production. The SOFC stack model was developed using the process flow sheet simulator Aspen Plus, which is of the equilibrium type. Various ranges of syngas properties gathered from different literature were used for the simulation. The results indicate a trade-off efficiency and power with respect to a variety of SOFC inputs. The HRSG located after SOFC was included in the current simulation study with various operating parameters. This paper describes IGFC power plants, particularly the optimization of HRSG to improve the efficiency of the heat recovery from the SOFC exhaust gas and to maximize the power production in the steam cycle in the IGFC system. HRSG output from different pressure levels varies depending on the SOFC output. The steam turbine efficiency was calculated for measuring the total power plant output. The aim of this paper is to provide a simulation model for the optimal selection of the operative parameters of HRSG and SOFC for the IGFC system by comparing it with other models. The simulation model should be flexible enough for use in future development and capable of predicting system performance under various operating conditions.     

Transient thermohydraulic computations in steam piping systems and comparison with start-up measurements in BWR plants

The safe design of piping systems in a nuclear power plant requires structural analysis for all specified static and dynamic loads, including fluid dynamic forces due to operational and loss-of-coolant accident (LOCA) transients. For the reliable prediction of fluid forces, boundary conditions such as the characterisation of a closing isolation valve with the proper friction coefficient need to be carefully chosen.

A valve model is described which implicitly determines the downstroke of the valve piston. Pre- and postcalculations were performed for the valve closure tests carried out during start-up at the BWR nuclear power plant at Krümmel, West Germany. The dynamic friction coefficient in a valve is introduced and its influence on the fluid dynamic forcing function in piping systems is examined.     

配PG9171E燃机余热锅炉主蒸汽参数的优化计算

联合循环系统中余热锅炉主蒸汽参数的确定 ,直接影响到蒸汽循环系统的性能和整个联合循环装置的效率。以某电厂烧重油PG91 71E燃机联合循环蒸汽循环系统为对象 ,建立了余热锅炉主蒸汽参数优化的热工模型。同时结合余热锅炉的设计 ,分别对主蒸汽压力、温度进行了优化计算。计算结果与国外公司的推荐数据完全一致 ,表明建立的模型正确 ,选定的优化约束条件合理 ,可供联合循环工程设计参考。     

Parametric Evaluation of Heat Recovery Steam Generator (HRSG)

Thermal efficiency of a combined cycle power plant depends strongly on a heat recovery steam generator (HRSG), which is the link between the gas turbine‐based topping cycle and steam turbine‐based bottoming cycle. This work is based upon the design of physical parameters of a HRSG. In this article, the physical parameters of a HRSG have been considered to study their implications on HRSG design by comparing the existing plant design with an optimized plant design. Thermodynamic analysis of HRSG for the two designs gives important outcomes which are useful for power plant designers. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21106     

Influence of the heat recovery steam generator design parameters on the thermoeconomic performances of combined cycle gas turbine power plants

This paper proposes a methodology to identify the most relevant design parameters that impact on the thermal efficiency and the economic results of combined cycle gas turbine power plants. The analysis focuses on the heat recovery steam generator (HRSG) design and more specifically on those operating parameters that have a direct influence on the economic results of the power plant. These results are obtained both at full and part load conditions using a dedicated code capable of simulating a wide number of different plant configurations. Two different thermoeconomic models aimed to select the best design point are proposed and compared: the first one analyzes the generating cost of the energy while the second one analyzes the annual cash flow of the plant. Their objective is to determine whether an increase in the investment in order to improve the thermal efficiency is worth from an economic point of view. Both models and the different HRSG configurations analysed are compared in the results section. Some parametric analysis show how the design parameters might be varied in order to improve the power plant efficiency or the economic results. Copyright © 2004 John Wiley & Sons, Ltd.     

Dynamic energy and mass balance model for an industrial alkaline water electrolyzer plant process

This paper proposes a parameter adjustable dynamic mass and energy balance simulation model for an industrial alkaline water electrolyzer plant that enables cost and energy efficiency optimization by means of system dimensioning and control. Thus, the simulation model is based on mathematical models and white box coding, and it uses a practicable number of fixed parameters. Zero-dimensional energy and mass balances of each unit operation of a 3 MW, and 16 bar plant process were solved in MATLAB functions connected via a Simulink environment. Verification of the model was accomplished using an analogous industrial plant of the same power and pressure range having the same operational systems design. The electrochemical, mass flow and thermal behavior of the simulation and the industrial plant were compared to ascertain the accuracy of the model and to enable modification and detailed representation of real case scenarios so that the model is suitable for use in future plant optimization studies. The thermal model dynamically predicted the real case with 98.7 % accuracy. Shunt currents were the main contributor to relative low Faraday efficiency of 86 % at nominal load and steady-state operation and heat loss to ambient from stack was only 2.6 % of the total power loss.     

基于EASY5仿真平台的火电厂热力系统仿真模型

采用模块化建模方法,合理划分部件,引入容积模块,使用状态变量解决系统中压力-流量之间的耦合关系,避免迭代计算,提高计算效率。以EASY5仿真软件为平台,开发了火电厂机组中各主要部件的模块库,方便不同结构系统模型的搭建。以某电厂1号机组为对象,结合热力系统的特点建立了机组热力系统仿真模型,对机组在额定工况下的特性进行了仿真分析,并与已有的试验数据对比,验证了仿真模型的有效性;在此基础上,进行了机组的动态特性仿真,获得了机组的瞬态响应特性,为机组控制性能的改善提供参考。     

Dynamic behavior of superheated steam and ways of control

A simple way of calculating the dynamic behavior of a superheater is presented. A comparison of the measured data with the calculated result verifies the accuracy of this simple method. It is the first time that a phase compensation for real roots, i.e., the twin lead/lag loop which is facile for engineering applications, is used in superheated steam temperature control. Numerous simulation results show that both the response time lapse and maximal dynamic deviation are greatly reduced. Moreover, a formula to calculate the setting parameters is presented, together with a practical example of its engineering application in superheated steam temperature control with single-stage attemperation in a power plant boiler. This method can remarkably improve the control performance of superheated steam temperature and makes it possible for one stage attemperation to be sufficient for the superheater of power plant boilers, thus simplifying the superheater system and reducing investment. Because the control performance is remarkably raised, the set values of the steam temperature control system can be raised above rated values and also the operational economy, without impairing the operation safety. __________ Translated from Journal of Power Engineering, 2007, 27(2): 199–203 [译自: 动力工程]     

Transient thermal modelling of heat recovery steam generators in combined cycle power plants

Heat recovery steam generator (HRSG) is a major component of a combined cycle power plant (CCPP). This equipment is particularly subject to severe thermal stress especially during cold start‐up period. Hence, it is important to predict the operational parameters of HRSGs such as temperature of steam, water, hot gas and tube metal of heating elements as well as pressure change in drums during transient and steady‐state operation. These parameters may be used for estimating thermal and mechanical stresses which are important in HRSG design and operation. In this paper, the results of a developed thermal model for predicting the working conditions of HRSG elements during transient and steady‐state operations are reported. The model is capable of analysing arbitrary number of pressure levels and any number of elements such as superheater, evaporator, economizer, deaerator, desuperheater, reheater, as well as duct burners. To assess the correct performance of the developed model two kinds of data verification were performed. In the first kind of data verification, the program output was compared with the measured data collected from a cold start‐up of an HRSG at Tehran CCPP. The variations of gas, water/steam and metal temperatures at various sections of HRSG, and pressure in drums were among the studied parameters. Mean differences of about 3.8% for temperature and about 9.2% for pressure were observed in this data comparison. In the second kind of data verification, the steady‐state numerical output of the model was checked with the output of the well‐known commercial software. An average difference of about 1.5% was found between the two latter groups of data. Copyright © 2007 John Wiley & Sons, Ltd.     

电厂热力系统的长期动态特性模型

热力系统的长期动态特性对各种火电机组的仿真或控制系统设计具有十分重要的意义。通过合理的机理分析和简化,从整体高度建立起热力系统的长期动态过程的数学模型,这一整体动态模型能较为合理地反映出长期动态过程中热力系统的蓄热与做功规律,弥补了现有火电机组动态模型的不足,更好地满足了机组长期动态特性分析与负荷控制策略研究的需要。最后以此为工具对某600MW超临界机组的长期动态特性进行了仿真研究,仿真结果合理正确。     

燃气-蒸汽联合循环电站机组配置及选型分析

对联合循环电站燃气轮机选型、蒸汽系统的选择、余热锅炉和汽轮机选型、机组轴系配置、动力岛布置、主要辅助设备的选择等方面进行了分析研究,为联合循环电站的设计和研究方向提供了建议。     

核电应急柴油发电机组滑油低压保护停机控制的设计优化

通过采用转速分段及增加短延时的改进方法,对当前核电应急柴油发电机组滑油低压保护停机控制设计进行了优化。经论证与试验表明:优化后的保护停机控制对机组起动及运行过程均起到了保护作用,同时确保了滑油压力的正常建立,避免了机组因受外部因素影响导致应急保护停机误动作,提高了机组起动的可靠性。该优化方案已经在核电厂应急柴油发电机组控制系统中得到广泛应用。     

Simulations and field tests of a reactor coolant pump emergencystart-up by means of remote gas units

The problem of the emergency start-up of a nuclear reactor coolant pump (RCP) by means of remote gas turbine power plant units is analyzed. A simulation model was developed which enabled a detailed simulation of the transient process occurring at the start up. The start-up of the RCP motor set was simulated for the cases of one and two gas units. Field tests were performed and the measured variable values agreed with the simulation results. Two gas units have been determined as a safe start-up scheme for the RCP motor set meeting the stringent protection restrictions imposed on the voltage and currents of the RCP and on 6.3 kV busbars of the safety-related house load. A model for deep rotor bars was experimentally confirmed as an effective means of the RCP motor set start-up transient simulation. Start-up procedures have been designed and adopted to conform to the safety procedures of a nuclear power plant     

余热锅炉动态数学模型建立及仿真

采用集总参数法建立了余热锅炉动态模型。根据余热锅炉的工作原理和特性,以能量和质量守恒原理为基础,详细论述了其内部蒸发器系统和单相介质换热器的数学模型算法,简化了汽水系统结建模仿真的复杂度。仿真结果表明该模型具有较好的动态响应特性,且模型运行稳定。     

Optimal synthesis and design of Heat Recovery Steam Generation (HRSG) via mathematical programming

Thermal efficiency of Combined Cycle Power Plants (CCPPs) depends strongly on the Heat Recovery Steam Generation (HRSG) design which links the gas cycle with the steam cycle. Therefore, the HRSG must be carefully designed in order to maximize the heat exchanged and to improve the overall performance of the plant.In this paper, a mixed integer non-linear programming (MINLP) model to simultaneously optimize the equipment arrangement, geometric design and operating conditions of CCPPs is proposed. General Algebraic Modelling System (GAMS) is used to implement and to solve the mathematical model. The HRSG model involves discrete decisions connected with the geometric design and the selection of tube diameters as well as the length and width of each solid fin. Continuous variables are used to model the operating conditions of the HRSG and steam turbines (ST). The solution strategy for the resulting model comprises two phases: the first one focuses the process optimization but considering only global energy and mass balances and this phase provides initial-bounds values for the second phase where the complete and rigorous model involving discrete decisions is solved. Different case studies with increasing complexity have been successfully solved. Model validation and results obtained from the MINLP model by considering different objective functions are discussed.